The heater valve connects the matrix to the stub pipes and its joints and o rings can break down over time.
Bmw e30 heater valve leaking.
The heater valve can also break if an incorrect radiator cap was fitted.
The value and heater core are separate components.
I have gone through a few heater valves.
It then flows through the valve out the bottom to the heater core green arrow.
This time i bought a rebuild kit from blunttech.
A quick check would be to confirm hot coolant is entering the valve at the upper hose red arrows and into the heater core through the lower hose green arrow.
This is the cause of 99 of wet passenger footwell issues.
Guts break replace whole valve with another used valve repeat.
There is a good article on how to replace the the value and heater core.
You will need to replace the two o rings that reside between the valve and the core.
In particular the heater valves get stuck or blocked hoses explode the auxiliary pump seizes up leaks and then the end drops off.
I was able to change both on my 325ic.
Water entering through the heater ac box.
Water entering from under the floor.
Why buy a new valve when the brass part does not wear out the kit includes everything but the brass shell.
Rebuild is a very simple process.
This feature is shared with the e32 and e38 but one thing that isn t is the restorative heating there s no rest button in the e31 and the auxiliary water pump appears superfluous.
Either of these conditions would point toward engine coolant and a leak in either the heater core or the control valve.
Make sure that you do not have a rust through area in the floor.
Hot coolant flows from the engine crankcase to the valve.